export const getmark = () => {
  const setWatermark = (str) => {
    const id = '1.23452384164.123412416'

    if (document.getElementById(id) !== null) {
      document.body.removeChild(document.getElementById(id))
    }

    //创建一个画布
    const can = document.createElement('canvas')
    //设置画布的长宽
    can.width = 200
    can.height = 120

    const cans = can.getContext('2d')
    //旋转角度
    cans.rotate((-15 * Math.PI) / 180)
    cans.font = '18px Vedana'
    //设置填充绘画的颜色、渐变或者模式
    cans.fillStyle = 'rgba(200, 200, 200, 0.30)'
    //设置文本内容的当前对齐方式
    cans.textAlign = 'left'
    //设置在绘制文本时使用的当前文本基线
    // cans.textBaseline = "Middle";
    //在画布上绘制填色的文本（输出的文本，开始绘制文本的X坐标位置，开始绘制文本的Y坐标位置）
    cans.fillText(str, can.width / 8, can.height / 2)

    const div = document.createElement('div')
    div.id = id
    div.style.pointerEvents = 'none'
    div.style.top = '30px'
    div.style.left = '0px'
    div.style.position = 'fixed'
    div.style.zIndex = '100000'
    div.style.width = document.documentElement.clientWidth + 'px'
    div.style.height = document.documentElement.clientHeight + 'px'
    div.style.background = 'url(' + can.toDataURL('image/png') + ') left top repeat'
    document.body.appendChild(div)
    return id
  }

  // 该方法只允许调用一次
  const watermark = (str) => {
    let id = setWatermark(str)
    setInterval(() => {
      if (document.getElementById(id) === null) {
        id = setWatermark(str)
      }
    }, 500)
    window.onresize = () => {
      setWatermark(str)
    }
  }
  const removeWatermark = () => {
    const id = '1.23452384164.123412416'
    if (document.getElementById(id) !== null) {
      document.body.removeChild(document.getElementById(id))
    }
  }
  return { setWatermark, watermark, removeWatermark }
}
